Omeprazole, chemically 5-methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-1H-benzimidazole and its therapeutic uses are disclosed in European Patent No. 5129. Omeprazole is a well-known gastric acid secretion inhibitor, and is useful as an anti ulcer agent. Omeprazole has a stereogenic center at sulfur and therefore exist as two optical isomers such as R-omeprazole and S-omeprazole (esomeprazole).
The salts of the enantiomers of omeprazole are described in WO 94/27988. PCT Publication No. WO 98/28294 disclosed esomeprazole in an amorphous form, a partly crystalline form A, and a substantially crystalline form B.
PCT Publication No. WO 2004/076440 A1 described crystalline forms, Form I and Form II, of esomeprazole, and its hydrates. PCT Publication No. WO 2004/020436 A1 described amorphous hydrates of esomeprazole magnesium and process for their preparation. PCT Publication No. WO 2004/002982 A2 described amorphous form esomeprazole free base and process for its preparation.
U.S. Pat. No. 6,369,085 described crystalline forms of esomeprazole magnesium, esomeprazole magnesium dihydrate, esomeprazole magnesium trihydrate and esomeprazole potassium.
The alkaline salts of (S)-enantiomer of omeprazole (esomeprazole), the pharmaceutical preparations of these salts and the method of treatment of gastric acid-related diseases using them are disclosed in U.S. Pat. No. 4,738,974, U.S. Pat. No. 5,877,192 and U.S. Pat. No. 5,714,504.
We have discovered a stable novel amorphous form of esomeprazole hydrate. The novel amorphous esomeprazole hydrate is stable over the time and has good flow properties and so, the novel amorphous hydrate is suitable for formulating esomeprazole.
The object of the present invention is to provide a stable novel amorphous form of esomeprazole hydrate, processes for preparing it and pharmaceutical compositions containing it.